A NOVEL HIGH-SCHOOL EXPERIMENT IN HYDROGENATION OF o m HATTIED. F. HAUB,ROOSEVELT HIGH SCHOOL, OAKLAND,CALIFORNIA "Unless you have some objection I would like to try to hydrogenate some oil. Everybody works on such topics as soap, paper, ink, perfume, and glass. I'd like to do something different and anyway I want to know more than what we discussed in class about this hydrogenation." Permission to investigate the subject and then attempt an experiment, provided it entailed no danger to himself or his classmates, was gladly granted to the young high-school student who wished to be original. From reading, the lad learned that such substances as Crisco, Cottolene, Kingnut Margarine, and other butter, lard, or olive oil substitutes were solid fats which had been made from liquid oils containing unsaturated compounds. Olive, oleo, cottonseed, and cocoanut oils contain olein, (C,7H3aCOO)3C3Hs.Linseed oil contains lmolein, (Cl,H31C00)3CaH5,and liuolenin, (C~Hd200)~CaHs.Cod-liver and manhaden oils contain clupanodonin, (C17H25COO)sC3H5.All these oils can be made to absorb hydrogen. The saturated compounds become solid fats suitable for foods or for making soaps. The reaction may be represented as follows: (CnH31C00)sCsH~4-6Hz -+ (CmH&00)3C3H5 Linolein Stearin 3Hz -+ (CnHssCOO)aC3Hs (CtrHsaCO0)sCaHs Olein Stearin
+
The hydrogen under pressure was blown through oil, heated to about 200°C. in an air-tight vessel. Nickel oxide, or finely divided nickel, suspended in the oil acted as the catalyzer. The more complete the hydrogenation the harder and more brittle the fat becomes, the completely hydrogenated product resembling tallow. All the information obtained from reading, though interesting, was too indefinite for the high-school student investigator, and he turned from books to manufacturers and advanced students of organic chemistry. His S. 0. S. letters brought back mainly discouragement. One company wrote him that hydrogenation of oil on a small scale was not practical. A professor of organic chemistry said it would he difficultto set up an apparatus for the hydrogenation of oil in a school laboratory, and there was no definite printed material on such an experiment as far as he knew. Only one letter held hopes for any success in the undertaking. Although the writer of this letter advised that all experimental work be carried on under the close supervision of the instructor, he expressed great confidence in the ultimate accomplishment of the project even when carried out on a small scaie. He suggested preparing a suspension of nickel formate in paraffin and then mixing enough suspension with cottonseed oil so that the oil would contain about 1% nickel. 1856
VOL. 8. NO. 9
HYDROGENATION OF OILS
1857
The experiment was performed as follows: hydrogen was generated in a Kipp generator, passed through a bottle containing about 200 cc. of concentrated sulfuric acid, and then through a calcium chloride tube. The reaction chamber was a liter Florence flask fitted with a four-holed stopper. One hole served as an entrance for the hydrogen delivery tube which extended to the bottom of the flask. From a second hole came a right-angle exit tube connected with a long mbber tube. This led the excess hydrogen away from the flame used in heating the oil. The third opening served for the introduction of a stirrer which later was found to be unnecessary as the continual bubbling of the hydrogen through the material caused sufficient agitation. A thermometer was inserted in the fourth hole. Sixteen grams of nickel formate and 75 cc. of paraffin were placed in the flask. The whole apparatus was flushed with hydrogen and the contents of the flask kept a t 240°C. for two hours with a slow stream of hydrogen constantly passing through. The green nickel formate began to turn black when a temperature of 200°C. was reached. Next day 800 cc. of cottonseed oil were added to the mixture in the flask. The whole was heated to 20OoC. Before heating, the hydrogen was run through the apparatus for several minutes. Throughout the experiment it was sent in a t a rate great enough to keep the mixture of oil and catalyst constantly and thoroughly stirred. No air was allowed to enter the apparatus. After about one and one-half hours of heating, approximately 20 cc. of the warm liquid was removed, filtered through cotton, and cooled to room temperature. The product formed a soft yellow solid which melted when the test tube was held in the hand. After another half hour the heat was removed and the mixture filtered through cotton. The filtrate when cooled to room temperature this time became a much firmer solid, yellow in color. Two methods of removing the yellow color were tried. One portion of the melted fat was filtered through activated carbon kept warm in a waterjacketed copper funnel. Another portion was placed in a beaker set in a bowl of ice water and beaten until a creamy product was obtained. The latter produced the better looking fat.
